list of discrete math applets

Prof. Eileen Peluso at Lycoming College sent me this list of discrete math applets put together by Prof. Susanna Epp of DePaul University.

This came from an ACM SIGCSE 2006 workshop.

maybe I should switch to FreeBSD or ubuntu...

I just upgraded one of my systems from FC4 to FC5. Now I can't login to the console except in failsafe mode. When I ssh into the system, I see:

$ ls
ls: error while loading shared libraries: librt.so.1: cannot open shared object file: No such file or directory

I figured out what was wrong today (5/22):

I had this in my ~/.bash_profile from some much earlier Java installation:

export LD_ASSUME_KERNEL=2.2.5

I commented out that line with LD_ASSUME_KERNEL, which apparently is no longer supported, and that fixed everything.

MacQTeX for online math quizzes

Macquarie University in Sydney, Australia has created some neat software for doing math quizzes online using MacQTeX with embedded Javascript in PDFs.

After FC5 upgrade, yum update stopped working

After I upgraded my GNU/Linux system from FC4 to FC5, yum update stopped working. This is now fixed.

yum couldn't find repositories, it couldn't read repomd.xml files, it really couldn't do anything at all. Firefox would load a repomd.xml off the net just fine, but wget would act as though the file didn't exist.

I traced the problem (in my case) to /etc/nsswitch.conf:

< hosts: files nisplus dns
--
> hosts: files dns

Why this blog

I started this blog so I could respond to something Mike Olson wrote at http://subclock.blogspot.com/2006/03/flat-is-new-open.html